Additive useful in oleaginous compositions

ABSTRACT

Oxazoline reaction products of hydrocarbon substituted dicarboxylic acid, ester, or anhydride, for example octadecenylsuccinic anhydride, with 2,2-disubstituted-2-amino-1-alkanols, such as tris-hydroxymethylaminomethane (THAM), and their derivatives are useful additives in oleaginous compositions, such as sludge dispersants for lubricating oil, or anti-rust agents for gasoline.

CROSS-REFERENCE TO RELATED CASES

This is a division of application Ser. No. 710,279 filed July 30, 1976,which is a Rule 60 Continuation of Ser. No. 530,235 filed Dec. 6, 1974,and now abandoned, which is a C.I.P. of Ser. No. 455,250 filed Mar. 27,1974, and now abandoned.

BACKGROUND OF THE INVENTION AND PRIOR ART

During the past decade, ashless sludge dispersants have becomeincreasingly important, primarily in improving the performance oflubricants and gasoline in keeping the engine clean of deposits, andpermitting extended crankcase oil drain periods. Most commercial ashlessdispersants fall into several general categories. In one category, anamine or polyamine is attached to a long chain hydrocarbon polymer,usually polyisobutylene, obtained by the reaction of halogenated olefinpolymer with polyamine as in U.S. Pat. Nos. 3,275,554; 3,565,592;3,565,804. In another category, a polyamine is linked to thepolyisobutylene through an acid group, such as long chain monocarboxylicacid, e.g., see U.S. Pat. No. 3,444,170 or long chain dicarboxylic acidsuch as polyisobutenylsuccinic anhydride, by forming amide or imidelinkages, such as described in U.S. Pat. Nos. 3,172,892; 3,219,666; etc.More recently, non-nitrogen ashless dispersants have been formed byesterifying long chain dicarboxylic acids; such as thepolyisobutenylsuccinic anhydride, with polyols, such as pentaerythritol,as in U.S. Pat. No. 3,381,022.

Reaction products of hydrocarbon substituted succinic anhydride, e.g.,the aforesaid polyisobutenylsuccinic anhydride, with compoundscontaining both an amine group and a hydroxy group have been suggestedor investigated in the prior art. For example, U.S. Pat. No. 3,272,746teaches the reaction of ethanolamine and diethanolamine, as well asvarious hydroxyalkyl substituted alkylene amines, such asN-(2-hyroxytheyl) ethylene diamine, N,N'-bis(2-hydroxyethyl) ethylenediamine, with alkenyl succinic anhydride to obtain ashless dispersantsfor lube oil. A hydroxy amine, such as diethanolamine, is reacted with along chain alkenylsuccinic anhydride in U.S. Pat. No. 3,324,033 to forma mixture of esters and amides, wherein some of the diethanolaminereacts through a hydroxy group to give an ester linkage, which anotherportion of the diethanolamine forms an amide linkage. U.S. Pat. No.3,364,001 teaches a tertiary alkanolamine reacted with an alkenylsuccinic anhydride to form an ester useful as a gasoline additive. U.S.Pat. No. 3,448,049 teaches dispersants, corrosion inhibitors andantiwear agents in lubricants and fuels by esterifying alkenyl succinicanhydride with a hydroxy compound made by reacting an alkanolamine withan unsaturated ester, amide or nitrile. U.S. Pat. No. 3,630,904 teachesreacting a hydroxy amine, with both short and long chain dicarboxylicacid. U.S. Pat. No. 3,484,374 teaches the polymeric condensationproducts of polycarboxylic acid or anhydride with various alkanolaminessuch as aminoethylethanolamine. N-methyldiethanolamine, etc. UnitedKingdom Specification No. 809,001 teaches corrosion inhibitorscomprising a multiple salt complex derived from the reaction product ofhydrocarbyl substituted dicarboxylic acids and hydroxy amines (including2-amino-2-methyl-1,3-propanediol [AMP] and trishydroxymethylaminomethane [THAM]) further complexed with mono- andpolycarboxylic acids (see Examples 17-19).

U.S. Pat. No. 3,576,743 teaches reacting polyisobutenylsuccinicanhydride with a polyol, such as pentaerythritol, followed by reactionwith THAM, (see Example 1). U.S. Pat. No. 3,632,511 teaches reactingpolyisobutenylsuccinic anhydride with both a polyamine and a polyhydricalcohol including THAM. U.S. Pat. No. 3,697,428 (Example 11) teachesreacting polyisobutenylsuccinic anhydride with a mixture ofpentaerythritol and THAM. United Kingdom Specification No. 984,409teaches ashless, amide/imide/ester type lubricant additives prepared byreacting an alkenyl succinic anhydride, said alkenyl group having 30 to700 carbon atoms, with a hydroxy amine including THAM.

SUMMARY OF THE INVENTION

As noted above, the prior art teaches dispersants formed fromhydrocarbyl substituted dicarboxylic acid material, usually alkenylsuccinic anhydride, reacted with various amino or hydroxy compoundseither through an amide, imide or ester linkage. In contrast to most ofthe prior art, the present invention is based upon the discovery thatreaction of hydrocarbyl dicarboxylic acid material, i.e. acid oranhydride, or ester, with certain classes of amino alcohols, undercertain conditions, will result in a heterocyclic ring structure, namelyan oxazoline ring, and that materials with this oxazoline ring includingderivatives thereof can be tailored for various functions, such asanti-rust agents, detergents, or dispersants for oleaginous compositionsincluding lube oil, gasoline turbine oils and oils for drillingapplications.

The compounds of the invention have at least 8 carbons in thesubstantially saturated aliphatic hydrocarbyl group and at least onecarboxylic acid group converted into an oxazoline ring as a result ofthe reaction of at least equimolar amounts of said hydrocarbonsubstituted C₄ -C₁₀ mono-unsaturated dicarboxylic acid material and a2,2,-disubstituted-2-amino-1-alkanol having 2 to 3 hydroxy groups andcontaining a total of 4 to 8 carbons.

THE HYDROCARBYL DICARBOXYLIC ACID MATERIAL

The hydrocarbyl substituted dicarboxylic acid material, i.e., acid oranhydride, or ester, used in the invention includes alpha-betaunsaturated C₄ to C₁₀ dicarboxylic acid, or anhydrides or estersthereof, such as fumaric acid, itaconic acid, maleic acid, maleicanhydride, chloromaleic acid, dimethyl fumarate, etc., which aresubstituted with a hydrocarbon chain containing at least 8 carbons,preferably from 8 to 49 or 50 carbons (branched or unbranched).

In general, these hydrocarbyl substituted dicarboxylic acid materialsand their preparation are well known in the art as well as several beingcommercially available, e.g., 2-octadecenylsuccinic anhydride.

The hydrocarbyl portion optionally should average from about 16 to about50 aliphatic carbon atoms per dicarboxylic acid group and besubstantially saturated. Further examples of the hydrocarbyl substituentportion are set forth in U.S. Pat. No. 3,458,444 which shows suchdicarboxylic acids reacted with tertiary amines to produce rust andsludge inhibitors.

Frequently these hydrocarbyl substituted dicarboxylic acid materials areprepared by reacting the unsaturated dicarboxylic acid material, usuallymaleic anhydride, with a 1-olefin, e.g. an olefin polymer of from about30 to about 50 carbons still retaining a terminal unsaturation.

THE AMINO ALCOHOL

The amino alcohol used to make the oxazoline dispersant is a2,2-disubstituted-2-amino-1-alkanol, having 2 to 3 hydroxy groups,containing a total of 4 to 8 carbon atoms, and which can be representedby the formula: ##STR1## wherein X is an alkyl, or hydroxy alkyl group,with at least one of the X substituents, and preferably both of the Xsubstituents, being a hydroxy alkyl group of the structure --(CH₂)_(n)OH, wherein n is 1 to 3.

Examples of such 2,2-disubstituted amino alkanols, include2-amino-2-methyl-1,3-propanediol,2-amino-2-(hydroxymethyl)-1,3-propanediol (also known astris-hydroxyaminomethane or THAM), 2-amino-2-ethyl-1,3-propanediol, etc.Because of its effectiveness, availability, and cost, the THAM isparticularly preferred.

THE OXAZOLINE REACTION CONDITIONS

The formation of the novel oxazoline materials, in a fairly higheryield, can be effected by adding about 1 to 2 mole equivalent of theaforesaid 2,2-disubstituted-2-amino-1-alkanol per mole equivalent of thedicarboxylic acid material, with or without an inert diluent, andheating the mixture at 140°-240° C., preferably 170°-220° C. for 1/2 to24, more usually 2 to 8 hours.

Although not necessary, the presence of small amounts, such as 0.01 to 2wt. %, preferably 0.1 to 1 wt. %, based on the weight of the reactants,of a metal salt can be used in the reaction mixture as catalyst toshorten the reaction times. The metal catalyst can later be removed byfiltration or by washing a hydrocarbon solution of the product with alower alcohol, such as methanol, ethanol, isopropanol, etc., or analcohol/water solution.

Alternatively, the metal salt can be left in the reaction mixture, as itappears to become stably dispersed, or dissolved, in the reactionproduct, and depending on the metal, it may even contribute performancebenefits to the oil or gasoline. This is believed to occur with the usedof zinc catalysts in lubricants.

Inert solvents which may be used in the above reaction includehydrocarbon oils, e.g., mineral lubricating oil, kerosene, neutralmineral oils, xylene, halogenated hydrocarbons, e.g., carbontetrachloride, dichlorobenzene, tetrahydrofuran, etc.

Metal salts that may be used as catalysts in the invention includecarboxylic acid salts of Zn, Co, Mn and Fe. Metal catalysts derived fromstrong acids (HCl, sulfonic acid, H₂ SO₄, HNO₃, etc.) and bases, tend todiminish the yield of the oxazoline products and instead favor imide orester formation. For this reason, these strong acid catalysts or basiccatalysts are not preferred and usually will be avoided. The carboxylicacids used to prepare the desired catalysts, include C₁ to C₁₈, e.g., C₁to C₈, acids, such as the saturated or unsaturated mono and dicarboxylicaliphatic hydrocarbon acids, particularly fatty acids. Specific examplesof such desired carboxylic acid salts include zinc acetate, zincformate, zinc propionate, zinc stearate, manganese (ous) acetate, irontartrate, cobalt (ous) acetate, etc. Completion of the oxazolinereaction can be readily ascertained by using periodic infrared spectralanalysis for following the oxazoline formation (oxazoline peak forms at6.0 microns), or by the cessation of water evolution.

REACTION MECHANISM OF THE OXAZOLINE FORMATION

While not known with complete certainty, but based on experimentalevidence, it is believed that the reaction of the hydrocarbylsubstituted dicarboxylic acid material, e.g., a substituted succinicanhydride, with the amino alcohol of the invention, e.g., twoequivalents of 2,2-disubstituted-2-aminoethanol such astris-hydroxymethylaminomethane (THAM), gives oxazonline, e.g.,bis-oxazolines, via the intermediacy of several discrete reactionspecies. If an acid anhydride is used, the initial transformationappears to involve the scission of the anhydride by the amino functionof one mole of the amino alcohol to yield an amic acid. Addition ofanother mole equivalent of amino alcohol is believed to form the amicacid amine salt, which then upon further heating, undergoescyclo-dehydration to the final bis-oxazoline product. The cataylsteffect of metal salts, such as zinc acetate (ZnAc₂), on oxazolineformation is very likely ascribable to the favorable polarization of theamide group by the zinc ion towards attack by the hydroxy function ofthe amino alcohol reactant. These reactions can be typified as followsin the case of bis-oxazoline: ##STR2## where R is the hydrocarbyl groupof the succinic anhydride, and each X in this case of usingtris-hydroxymethylaminomethane (THAM) represents a --CH₂ OH group.

In contrast to the above oxazoline formation using the disubstitutedamino alcohol, if the amino alcohol has no substituents as in2-aminoethanol, or has only one substituent in the 1- or 2-position asin 2-amino-1-propanol, 2-amino-1-butanol, and related mono-substituted2-aminoethanols, the aminoalcohol fails to undergo the aforesaidoxazoline reaction. Instead, these other amino alcohols will react withthe succinic anhydride to give almost exclusively succinimide productsas illustrated in the following reaction. ##STR3## wherein R and X areas previously defined. In no instances were discernible amounts ofbis-oxazoline products found in experiments on the above reactions.

Condensation of about 1 mole equivalent of the aforesaid2,2-disubstituted amino alcohol with about one mole equivalent of saiddicarboxylic acid material affords the mono-oxazoline ester.

USE OF THE OXAZOLINE ADDITIVE IN OLEAGINOUS COMPOSITIONS

The oil soluble oxazoline reaction products of this invention can beincorporated in a wide variety of oleaginous compositions. They can beused in lubricating oil compositions, such as a automotive crankcaselubricating oils, automatic transmission fluids, etc. in concentrationsgenerally within the range of about 0.01 to 20 weight percent, e.g., 0.1to 10 weight percent, preferably 0.3 to 3.0 weight percent, of the totalcomposition. The lubricants to which the oxazoline products can be addedinclude not only hydrocarbon oils derived from petroleum, but alsoinclude synthetic lubricating oils such as polyethylene oils; alkylesters of dicarboxylic acid; complex esters of dicarboxylic acid,polyglycol and alcohol; alkyl esters of carbonic or phosphoric acids;polysilicones; fluorohydrocarbon oils; mixtures of mineral lubricatingoil and synthetic oils in any proportion, etc.

When the products of this invention are used as multifunctionaladditives having detergents, anti-rust properties in petroleum fuelssuch as gasoline, kerosene, diesel fuels, No. 2 fuel oil and othermiddle distillates, a concentration of the additive in the fuel in therange of 0.001 to 0.5 weight percent, based on the weight of the totalcomposition, will usually be employed.

When used as an antifoulant in oil streams in refinery operations toprevent fouling of process equipment such as heat exchangers or inturbine oils, about 0.001 to 2 wt. % will generally be used.

The additive may be conveniently dispensed as a concentrate comprising aminor proportion of the additive, e.g., 2 to 45 parts by weight,dissolved in a major proportion of a mineral lubricating oil, e.g., 98to 45 parts by weight, with or without other additives being present.

In the above compositions or concentrates, other conventional additivesmay also be present including dyes, pour point depressants, antiwearagents such as tricresyl phosphate or zinc dialkyldithiophosphates of 3to 8 carbon atoms in each alkyl group, antioxidants, such as N-phenylα-naphthylamine, tert-octylphenol sulfide, 4,4'-methylenebis(2,6-di-tert-butyl phenol), viscosity index improvers such asethylene-propylene copolymers, polymethacrylates, polyisobutylene, alkylfumarate-vinyl acetate copolymers and the like, de-emulsifiers such aspolysiloxanes, ethoxylated polymers and the like.

This invention will be further understood by reference to the followingexamples, which include preferred embodiments of the invention.

EXAMPLE 1

A bis oxazoline of octadecenylsuccinic anhydride and2-amino-2-methyl-1-propanol (AMP) was prepared as follows:

A mixture of 527 gm. (1.5 moles) of 2-octadecenylsuccinic anhydride,commercially available from Humphrey Chemical or Monsanto, St. Louis,Mo., 200 mol. of tetrahydrofuran (THF) as solvent, 4 gm. of zinc acetatedihydrate (ZnAc₂.2H₂ O) as a catalyst and 276 gm. (3.0 mole) of2-amino-2-methyl-1-propanol (AMP) was charged into a laboratory glass 1liter reaction flask, equipped with a bottom draw-off, a thermometer, acharging funnel, a nitrogen blend, and an overhead condenser equippedwith a Deane-Starke water trap. The flask was heated in an oil bath.When the reaction temperature had risen to 72° C., the THF solventdistilled off. Further heating at about 200° C. for several hours gavethe expected quantity of water, i.e., about 81 grams of water in thetrap. Vacuum distillation of the crude mixture produced an amber liquidas residue which boiled at 245°-251°C. (ca. 1 mm Hg). Infrared and NMRspectral data of said residue confirmed the bis-oxazoline structure.Analysis gave the following: 75.60 wt. % carbon (calculated 75.89 wt %);11.53 wt. % hydrogen (calculated 11.46 wt. %); 5.38 wt. % nitrogen(calculated 5.89 wt. %); and 7.12 wt. % oxygen (calculated 6.76 wt. %).The calculated amounts were based on C₃₀ H₅₄ N₂ O₂.

EXAMPLE 2

A mixture of 21 gm. (0.1 mole) of diisobutenyl-succinic anhydride in 100ml. of THF was aminated with tris-hydroxymethylaminomethane by theportionwise addition of 24.2 gms. (0.2 mole) of the latter to themixture in the glass reactor, previously described, at about 35° C.After evaporation of the THF solvent, the mixture was heated in the oilbath at about 200°-220° C. for about two hours. The infrared spectrum ofthe reaction product drawn from the flask showed a strong absorptionband at 6.0 microns showing the oxazoline structure had formed. Analysisshowed that the final product contained 58.07 wt. % carbon; 8.60 wt. %hydrogen, and 7.00 wt. % nitrogen.

EXAMPLE 3

178 grams (2.0 moles) of 2-amino-2-methyl-1-propanol (AMP) weregradually added to 210 gm. (1.0 mole) of 2-octenyl-succinic anhydride.The reaction temperature peaked to 130° C. during the AMP addition. Themixture was thereafter heated to 196° C. for three hours, followed byaddition of 28 gm. of AMP and subsequent heating for 6 hours at 194° C.

EXAMPLE 4

210 gm. (1.0 mole) of 2-octenylsuccinic anhydride was gradually added to267 gm. (3.0 moles) of AMP containing 4.0 gm. of zinc acetate dihydrate.The reaction mixture was refluxed for several hours. During this period,excess amino alcohol and water was collected using a distilling headmounted on the reactor. The reaction was stopped when water ceased todistill over. Distillation of the crude product afforded a clear liquidwhich boiled at 171°-173° C. (0.15 mm Hg). The infrared spectrum of thebis-oxazoline product exhibited a strong absorption band at about 6microns. Analysis of the reaction product gave 71.11 wt. % carbon(calculated 71.59 wt. %); 10.28 wt. % hydrogen (calculated 10.52 wt. %);and 8.25 wt. % nitrogen (calculated 8.35 wt. %). The calculated figureswere based on C₂₀ H₃₅ N₂ O₂.

EXAMPLE 5

A mono-oxazoline of octadecenyl succinic anhydride andtris-hydroxymethylaminomethane was prepared as follows:

A mixture of 87.8 gm. (0.25 mole) of 2-octadecenyl succinic anhydrideand 30.75 gm. (0.25 mole) of tris-hydroxymethylaminomethane and 0.5 gm.of zinc acetate dihydrate were mixed together and gradually heated to210° C. in the apparatus of Example 1. The reaction was continued atthis temperature until the evolution of water ceased. A sample of theproduct was recrystallized froom acetone/hexane solution and submittedto elemental analysis which showed 71.00 wt. % carbon (calculated 71.68wt. %); 10.33 wt. % hydrogen (calculated 10.41 wt. %); and 4.12 wt. %nitrogen (calculated 3.22 wt. %). The calculation was based on C₂₆ H₄₅NO₄. The infrared spectrum of the product featured strong ester andoxazoline absorption and at 5.75 and 6.0 microns, respectively. Themolecular weight of the product by osmometry was found to be 2324.

EXAMPLE 6

21 gm. (0.1 mole) of diisobutenylsuccinic anhydride was mixed with 12gms. (0.1 mole of tris-hydroxymethylaminomethane in the presence of 0.5gm. of zinc acetate dihydrate and heated to about 140° C. At thistemperature, water began to distill from the reactor. Heating wasgradually increased to about 180°-190° C. over a four hour period duringwhich 36 milliliters of water were collected. The infrared spectrum ofthe reaction mixture revealed the presence of mono-oxazoline product inhigh yield.

EXAMPLE 7

584 gm. (1.5 moles) of 90% active 2-octadecenyl-succinic anhydride and4.0 gm. of zinc acetate dihydrate was slurried in 200 ml. oftetrahydrofuran. To this was added 363 gms. (3.0 moles) of2-amino-2-(hydroxymethyl)-1,3-propanediol. The temperature was graduallyraised to 160° C. effectively removing most of the solvent. Followingthis the mixture was heated to 208° C. over a three-hour period duringwhich water distilled. The contents were found to have a prominentabsorption band at about 6.0 microns. Recrystallization of the crudereaction product gave a white solid which melted at 104°-106° C. Therecrystallized product showed the following analysis: 66.80 wt. % carbon(calculated 66.83 wt. %); 9.86 wt. % hydrogen (calculated 10.10 wt. %);4.59 wt. % nitrogen (calculated 5.20 wt. %); and 18.40 wt. % oxygen(calculated 17.82 wt. %). Calculated values were based on C₃₀ H₅₄ N₂ O₆.

The product of Example 7 were tested for its effectiveness as a gasolineanti-rust agent. This product was first dissolved in xylene, and thesolution was added to the gasoline to incorporate the additive at atreat rate of 10 pounds of oxazoline additive per thousand barrels ofgasoline, i.e., about 0.024 wt. %. The gasoline so treated was thentested for rust according to ASTM D-665M rust test. In brief, this testis carried out by observing the amount of rust that forms on a steelspindle after rotating for an hour in a water-gasoline mixture. In thiscase, the oxazoline treated gasoline gave no rust indicating that it wasvery effective as an anti-rust additive since the untreated gasolinewill give rust over the entire surface of the spindle.

In other identical testing (except that the treat rate was 6.25 lbs. ofadditive product per 1000 barrels of gasoline), the reaction product ofExample 5 was found to be very effective as an anti-rust additive forgasoline.

The oxazoline reaction products of the invention which are primarilyuseful as an anti-rust additive and/or detergent for gasoline willgenerally have hydrocarbyl substituents numbering from about 12 to about49 carbons (preferred is about 18 as exemplified by 2-octadecenyl);whereas, for applications as a dispersant or detergent in lubricants itis preferred that the hydrocarbyl substituents number from about 30 to49 carbons, e.g. 35 to 45 carbons.

Both the chemical structure and number of the oxazoline rings have aninfluence on the functionality of the additive compounds of theinvention. The bis oxazoline additive wherein THAM was the amino alkanolappears of highest efficacy in its anti-rust properties.

In summary, effective additives for oleaginous compositions can beprepared by reaction of a hydrocarbon substituted dicarboxylic acidmaterial with a 2,2-disubstituted-2-amino-1-alkanol under conditionssuch that formation of simple esters, imides or amides is eliminated, orat least minimized, so that a substantial proportion of the aminoalkanolis converted into oxazoline rings. Infrared spectrum on some of theaforesaid Examples indicate that a major proportion, and in some casesessentially all, of the aminoalkanol was converted to oxazoline rings.

The invention in its broader aspect is not limited to the specificdetails shown and described and departures may be made from such detailswithout departing from the principles of the invention and withoutsacrificing its chief advantages.

What is claimed is:
 1. A petroleum fuel composition comprising: a majoramount of petroleum fuel and in the range of 0.001 to 0.5 wt. % ofbis-oxazoline of a molar proportion of a hydrocarbon-substituted C₄ -C₁₀mono unsaturated dicarboxylic acid material selected from the groupconsisting of dicarboxylic acid, ester and anhydrides thereof, having inthe range of from about 8 to 49 carbon atoms in said hydrocarbonsubstituent; reacted with about two molar proportions of a2,2-disubstituted-2-amino-1-alkanol having 2 to 3 hydroxy groups andcontaining a total of 4 to 8 carbons of the formula: ##STR4## wherein Xis alkyl or hydroxy alkyl, said alkyl groups having 1 to 3 carbon atoms,and at least one of said X is a hydroxy alkyl group of the structure--(CH₂)_(n) OH where n is 1 to 3; at a temperature in the range of about140 to 240° C. for about 1/2 to 24 hours with the removal of about threemolar proportions of water to thereby produce said bis-oxazoline havingthe structure ##STR5## wherein R is said hydrocarbon substituent and Xis as defined above.
 2. A composition according to claim 1, wherein saidhydrocarbon substituted dicarboxylic acid material is alkenyl succinicanhydride and said fuel is gasoline.
 3. A composition according to claim2, wherein said alkenyl group contains about 18 carbon atoms.
 4. Acomposition according to claim 3, wherein said amino-1-alkanol is2-amino-2-methyl-1-propanol.
 5. A composition according to claim 3,wherein said amino-1-alkanol is tris-hydroxy-methylaminomethane.